CLASSIFICATION OF PHRYNOSOMA : HORNED TOAD
PHYLUM :- CHORDATA (Notochord, dorsal tubular nerve cord present and gill slits present )
Group :- CRANIATA ( Definite head. Cranium with brain present )
Sub-phylum :- VERTEBRATA ( vertebral column present)
Division :- GNATHOSTOMATA ( Jaws and paired appendages present )
Super class :- TETRAPODA ( Paired limbs, lungs, bony skeleton and cornified skin)
Class :- REPTILIA ( Scaly vertebrates with right and left aortic arches. Single condyle, pulmonary respiration. Embryo with amnion and allantois ).
Sub-class :- DIAPSIDA ( Skull with two temporal openings separated by postorbital and squamosal ).
Order :- SQUAMATA ( Lizards and snakes with horny epidermal scales or shields. Quadrate bone movable. Vertebrae procoelous. Anal opening transverse).
Sub-order :- SAURIA ( Lizards. Body slender, limbs 4. Pterygoid in contact with quadrate. Eyelids movable )
FAMILY :- IGUANIDAE (Limbs normal. Teeth homodont).
GENUS :- Phrynosoma
Phrynosoma is a New World lizard and is chiefly found in Eastern Washington, Kansas to California and Mexico.
HABIT AND HABITAT
Phrynosoma is well adapted for desert life. It lives on dry ground and sandy places. It can live without water for a long time. It feeds on ants and other small insects. In the sunlight it feels happy but as night approaches it burries itself in the sand keeping only the head and horns exposed.
GENERAL CHARACTERSTICS OF PHRYNOSOMA : HORNED TOAD
- Commonly known as Horned toad.
- Body broad, flat and spiny. Scales of head region are enlarged like horns while regular spiny scales are found allover the body. Body divided into head, neck, trunk and tail.
- Dorsal surface is yellowish grey. 2 pairs of large spines are found on each sub-lateral position andnumber of runs of small spines present over the trunk. Small and large spines present on the tail. Spines also present on forelimbs and hind limbs. Digits are clawed for digging sand.
- Undersurface of thigh contains pores in both sexes and is covered with keeled scales.
- Head contains 5 spikes on each side, one post-orbital, three temporal and one occipital. Head contains eyes, nostril and prominent helmet. A pair of barn-like process are present just below helmet.
- The sides of the lower jaw project in the shape of prominent ledges and are protected by a series of small spines.
- Tongue is fleshy and non-protrusible. Eyelids are complete. Teeth are usually homodont or pleurodont. Vertebrae opisthocoelous.
- Nostrils are provided with valves, which prevent sand to enter into nostrils. External ear opening present near born like spine.
- Tail is short.
Phrynosoma is well adapted for arid zone living. When disturbed, the lizard squirts a tiny stream of blood from the eye which can go upto a distance of two feet and thus it protects itself.
The animal contains rough skin, spines allover the body and above features, hence it is Phrynosoma.
- Book of Practical Zoology VERTEBRATE by S.S.LAL – Rastogi Publications.
- SOURCES OF IMAGES – https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.thoughtco.com%2Fhorny-toad-lizard-4767243&psig=AOvVaw3QI2Lz6OStBS0lqsN_qxYK&ust=1604560412708000&source=images&cd=vfe&ved=2ahUKEwii5NC8q-jsAhU74XMBHVXvCMUQr4kDegUIARDhAQ